In general, when extruding a billet made of a metal material such as aluminum or an alloy material thereof by an extrusion press machine, an extrusion stem is attached to a front end part of a main ram driven by a hydraulic cylinder. A container is pressed against a die. In that state, the billet is stored in the container by the extrusion stem or the like. Further, the main ram is made to further advance by being driven by the hydraulic cylinder whereby the billet is pressed by the extrusion stem. Therefore, a shaped product is pushed out from an outlet part of the die.
Even in the past, there are many types of extruded products and the frequency of changing dies had increased. In recent years, however, the production of extremely small lots of diverse products has been increasing. Along with this, the frequency of changing dies has also dramatically increased. As opposed to this, in the conventional die changing device, although the die changing time has been shortened, there has been a demand for further reduction of time. Further, the conventional die changing device uses a hydraulic cylinder, so the hydraulic cylinder is long and a large space is required. Furthermore, according to PLT 1, a die is changed by driving a chain installed on the container side of the end platen to thereby make the die move from an extrusion position to a changing position outside the extrusion press and changing the dies, then again move the die to the extrusion position. The chain is installed in the vicinity of the heated die and container, so the chain became high in temperature and maintenance of the chain took more time compared with a usual one used cold.